1. Field of the Invention
The present invention relates to a dicing/die-bonding film. The dicing/die-bonding film is used for subjecting a work to dicing in such a state that an adhesive for sticking a chipped work (semiconductor chip etc.) to an electrode material is arranged on a work (semiconductor wafer etc.) before dicing. Further, this invention relates to a method of fixing a chipped work by using the dicing/die-bonding film. Also, this invention relates to a semiconductor device having a chipped work adhesive-bonded by the fixing method.
2. Description of the Related Art
A semiconductor wafer on which a circuit pattern was formed is subjected to dice into chipped works (dicing step), as necessary after back-grinding to regulate the thickness. In the dicing step, the semiconductor wafer is generally washed at suitable fluid pressure (usually, about 2 kg/cm2) to remove a cut layer. Then, the chipped work is adhesive-bonded onto an adherend such as a lead frame (mounting step), and then processed in a bonding step. In the mounting step, an adhesive is conventionally applied onto the lead frame or the chipped work. In this method, however, a uniform adhesive layer is hardly formed, and application of the adhesive requires a special unit and a long time. Accordingly, a dicing/die-bonding film having an adhesive layer adhering semiconductor wafer thereto in the dicing step and providing a chip-mounting necessary for the mounting step has been proposed (see e.g. in JP-A 60-57642).
The dicing/die-bonding film described in JP-A 60-57642 supra comprises an adhesive layer arranged in a releasable manner on a supporting base material. That is, a semiconductor wafer retained on an adhesive layer is diced, and the supporting base material is stretched to remove each chipped work together with the adhesive layer, and each work is recovered and fixed via the adhesive layer to an adherend such as a lead frame.
To prevent problems such as dicing inability and dimensional mistakes, the adhesive layer of this dicing/die-bonding film is desired to have an ability to sufficiently maintain the semiconductor wafer and an ability to sufficiently release the chipped work together with the adhesive layer from the supporting base material after dicing. However, it is not easy to balance both the abilities. When sufficient retention is required of the adhesive layer particularly in a system of dicing a semiconductor wafer with a rotating circular tooth, the dicing/die-bonding film satisfying the above characteristics is hardly obtained.
To overcome the problem, various improved methods are proposed (see e.g. on JP-A 2-248064). JP-A 2-248064 supra proposes a method which comprises allowing a UV-curing pressure-sensitive adhesive layer to be present between the supporting base material and the adhesive layer, then curing it by UV rays after dicing to lower the adhesion between the pressure-sensitive adhesive layer and the adhesive layer thereby releasing the layers from each other to facilitate pickup of the chipped work.
By this method, however, there are the cases where the adhesive layer achieving retention for the dicing step and releasability for a subsequent step in good balance is hardly formed. For example, when a large chipped work of 10 mm×10 mm or more is to be obtained, its area is so great that the chipped work cannot be easily picked up with a general die bonder.